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K. SLIDELL ET AL May 30, 1933 -PROCESS OF PRODUCING CELLULAR BUILDING MATERIAL Re. 18,844

ZShBBtS-SIIGt 1 Original Filed Aug. 1, 1929 K. SLIDELL ET AL May 30, 1933. PROCESS OF PRODUCING CELLULAR BUILDING MATERIALRe. 18,844

2 Sheets-Sheet 2 o i Filed Aug. 1, 1929 eff; U672 fifis Reissued May 30, 1933- process possesses form for the purpose of ing out and dissemination of tile of the organic which might UNITED STATES PATENT oi-"rlca KEEPER SLIDELL, OF MADISON, WISCONSIN, AND SHERMAN Q. LEE, OF WEST CHICAGO, ILLINOIS, ASSIGNORS, BY MESNE ASSIGNMENTS, T0 AMERICAN FACE BRICK RIREARCH CORPORATION, CORPORATION OF ILLINOIS rnodass or rnonuoino CELLULAR BUILDING MATERIAL Original No. 1,845,350, dated February 16, 1932, Serial No. 382,749, filed August 1, 192?. Application for reissue filed March 19,

This invention is directed to a process of treating. argillaceous material in granular producing building blocks or units and other articles of manufacture.

The product produced by the present such qualities as economy of raw materials, saving of transportation costs, high speed in erection when the product is used as-a building unit, superior insulation against heat and cold, and imperviousness to moisture.

The material is of a cellular or vesiculated character throughout, having a structure very similar to that of baked bread, which readily floats in [water and is stron enough for the supporting walls of buildin s, and is non-absorptive of moisture.

he present process is directed to the production of this material in predetermined forms and sizes, which maybe vused either in the orifginal form as deliv ered from the kiln or urnace, or in smaller sections produced by cutting or otherwise dividing the original block or slab; and the various steps of the process are harmoniously related to the development of a relatively uniform cellular structure throughout the mass, and to the avoidance of conditions which would tend to produce violent ebullition or explosive violence in the discharge of gases, which would beprejudicial in secur- 1n the desired uniformity of structure.

- rovisio'n is therefore made, in the performance of the process, for the initial burnmatter originally contained in the raw material and for the elimination of other gas forming .materials disrupt the continuity and relative uniformity of the cellular structure by violent'-ebullitions in the- I the process, so that a gradual and'uniform swelling of the material at the in the process willbe insured.-

process is of argillaceous claysand the more volabloating stage of proper stage. bl

character, such as shales ordinarilyv employed in brick making. The first step in the proc I ess is to grind or otherwise break up the clay,

1932. Serial No. 6mm.

into comparatively small which are preferably of a size larger than about a sixth of'an I fineness down to dustlike particles. preliminary grinding into comparatively small dimensions is desirable in order to in penetration of the preliminary'heating in a rotary or other furnace and heated until type of agitating it is slightly below the fusing stage, but without increasing the heat to a degree which will modify its granular character or cause granules, none of inch, and of ecreasing ji This the particles to become sticky and adherent. 1

After preheating, and preferably while in the heated condition, a non-agitating furnace or heating chamber and is quiescently heated to a temperature at which it fuses and pufl's. It is then slowly cooled and annealed and finally delivered in form to be used either in the original form of a block or slab, or cut into smaller units if desired.

Almost any arg'illaceous material is suit able for making this material. The purer fire clays may be so difficult to fuse as tobe impracticable for use, but most'clays and shaleswill make this material, Carbon, sulit is then transferred to d phur and iron are constituents of cl'ayfthatq contribute to or are perhaps essential to ing a clay capable of being bloated.

he drawings ill1 1stra.te .moreor. less diagrammatically the conditio of theematerial during thevariousistages of I the process, tOF

getherwith diagrammatic representation of so much of the kiln in which oated as isjnec'essa ry to an of the process andthe'nature resulting therefrom. I

Figure 1 is a ,vie f showing a pile ofthe granular ,matei'ial :in its original broken up or disintegrated condition; j

Fig. 2 a View showing the condition of a,

the material is understanding of the product 9 a fused surface skin or layer;

Fig. 3-is a view show ng the final condition of the material after it has been com- I we do not limit pletely bloated; and

Fig. 4 is a diagrammatic view of a simplified form of kiln or furnace adapted for the performance of the present process.

The material is ground or otherwise broken up into granules orparticles A to a fineness approximately suitable for brick making, as indicated in Figure 1. We have found that by breaking it up so that it will go through a one-sixth inch mesh produces I a suitable granular mass for future treatment, although the raw material to this degree of fineness. We preferably (grind it dry and in some type of rinder use for grindin brick clays or sha es.

he ground material is placed in some type of agitating kiln where it is rapidly heated to a temperature of from 1500 to 1800 F., the object being to heat to the highest practicable temperature at which the granular condition of the without fusion. We have found a rotary type kiln very suitable for this purpose, but do not limit ourselves to the use ofthis type of kiln. The purpose of this heating is to dry and uniformly heat the material without fusing it. As the material nears the temperature above stated, it first be ins to give off internally created gases, an then, if continued above this, become sticky. These gases have an affinity for oxy en, and to prevent the giving off of too muc -of these gases we find it advantageous to heat the material in an atmosphere as nearly devoid of oxygen as possible. I

While still in the granular stage, the material is transferred to some type of kiln in which the material can be quiescently heated to a. higher temperature. The temperature is for most material run up to 2000 or 2300 F. We have found a stationary semi-muffle type of urpose. A refractory slab B is utilized on which to deposit the material. This slab is supported above the floor of the furnace so that the heat can reach the material both from above and below. We find it advantageous to transfer he material from the agitating kiln to the quiescent kiln by gravity. The material is leveled, 'or if desired is spread between side forms C over the refractory slab of the quiescent kiln directly on top of sand or other material of a thin layer D that will keep it from, sticking to the slab. The side forms maybe of metal which will scale under heat, the scale parting from the metal body, or carborundum or the like may be used, or strips of the present product, which will fuse onto the mass under treatment and may be removed therewith, and thereafter trimmed from the completed 'medium'serves to prevent adherence of material will be preserved furnace quite satisfactory for this block and again used as forms in succeeding operations. This anti-sticking medium must be of some material that will part in itself, or which is a very cheap or waste product. We find that in addition to sand and gravel, graphite and talc can be used.

In view of the fact that the anti-sti-ckirlllg t e material under treatment, and serves, after bloating, to permit the block or slab of material to be moved forwardl over the floor of the furnace, we employ the term lubricant as aproper designation for a'material having these attributes. After the material is placed on the bed of anti-sticking material, it is leveled or struck off to a uniform depth, as in Fig. 2. This is done so that the heat will penetrate the material uniformly throughout themass, and also so, that the finished product will be of reasonably uniform thickness or dimensions. 1

The first action of the heat when the material is subjected to this higher temperature is to fuse the surface particles so that they flow together and form a vitrified sealing skin E. This skin imprisons in the material a part of the air that is between the particles. As the heat penetrates beyond the skin it fuses or welds the particles together, expands the imprisoned air and liberates the heatgenerated ases within the material. These gases are of sulphur, carbon and other gas producing substances in the material. This expanded air and liberated gas forms bubbles or cells throughout the fused or vitrified mass, so'

that-it has very much structure ofyeastleavened dough, the cell walls being of vitrified'material and the identity of the original 0 formed from the breaking down Wehave found thatmaterial preheated to 1800", when placed in the bloating temperature,bloats to a suitable degree when heated from ten to fifteen minutes original thickness, so that a two inch bed of material will bloat to four inches in twenty to thirty minutes.

In most cases the material will bloat to the desired level without rolling, but if a particularly level surface or a uniform thickness of the bloated material is desired, we may roll the top while it is .hot. Furthermore, if a special shape is desired, the'bloated material while still plastic can be rolled in various ways to dimensions.

To keep the material from sticking to the roller, we use a roller that is much cooler than the hot clay, or sprinkle the top surface with sand or other parting material; and for most purposes the material will be bloated for each inch of while in theform of a column having parallel top and bottom surfaces either for use as a completed block or slab of that form or 1 to facilitate cutting to smaller blocks or slabs without excessive waste. For some purposes we can deform the slabs by top and bottom rollers, as, for instance, in making some forms of roofing tile.

A continuous slab or column of indefinite length can be produced if desired by introducing the material continuously or in charges, and fusing new material tothat previously bloated, the completed portion of the slab being moved forwardly from time to time to make way within the furnace for incoming charges of material.

hen cool, the material retains its cellular structure and becomes solid and somewhat brittle. If it is cooled rapidly, it shatters from the strains of contraction; therefore,

we find that it is necessary to cool the ma-' terial quite slowly to counteract this self-destructive tendency. It can be quickly cooled down to a cherry color without injury, but below this stage it must be cooled very slowly. \Ve find that with the clays we have used, a four inch slab requires about three to six hours to reduce to a handling temperature.

During the preheating stage, it is desirable to maintain a neutral or reducing atmosphere in order to burn out only the more volatile or explosive of the gases which are'relied upon to bloat the material during the second stage of the process.

It is also desirable, in the bloating stage, to maintain a neutral or reducing atmosphere, but after the material has reached the annealing chamber, it may be desirable at an early stage in the annealing to admit additional oxygen in order to oxidize the surface in securing the desired coloration. It is also possible to vary thecolo'ration in various ways, either by the use of a surface coating of clay or other material specially selected for its coloration, or by otherwise treating the product in ways well understood in the brick making art in order to secure the desired efiect.

It may also be desirable to-vary the exposed surface texture of the mass when undergoing the bloating treatment, by sprinkling a layer of granular material of a particular or uniform degree of fineness over thesurface, so that the resultant pebbled or roughened surface effect will be modified in the desired manner. I

It is obvious that both the surface texture and coloration may be regulated by the spreading of a thin surface'layer of granular materialof the desired size, which also possesses the property of producing the intended coloration.

Although for some purposes the block or slab may be used in the form in which it comes from the furnace and presenting the pebbled top surface texture characteristic of this material before cutting, it will be found that for many purposes it is necessary to cut the material into shapes. For bricks, building block, roofing tiles, roofing slabs, etc., we cut the slab as it comes from the furnace, by means of abrasive wheels, or other cutting devices. For accurately shaped units, we grind the top and bottom surfaces, but for most units, these surfaces, more or less pebbled or rough, can be left just as they come from the kiln, since the pebb-ling pre sents an attractive texture especially desirable when the material is used for exterior wall building purposes.

This material has a highly cellular structure. Thecells F are spherical and preferably none are over one-eighth of an inch in diameter, and are separated by continuous cell walls G of vitrified material. Interspersed with larger cells will be finer ones, some so fine as to be invisible to the eye. Its weight varies with the degree of pufling to which it is subjected, but we find in general that the material that has been bloatedso as to have a weight of twenty to fifty pounds per cubic foot is entirely suitable for building materials for various purposes. Its compressive strength varies with the bloating temperature control and atmosphere control exercised. in preheating and bloating, and also with the care with which it has been annealed. Samples which we have tested range from 630 to 2690 pounds per square inchf l/Ve find that about 1500 pounds per square inch is the average for the material we make into building units.

The material is practically impervious to moisture even when subjected to considerable hydrostatic pressure, due to the fact that the vitrified, cell walls afford no interconnecting pores or crevices for the passage of water. The material is easily penetrated by nails:

It can be cut with a metal saw as well as by an abrasive wheel. The cut surfaces are usually of a grayish purple, but they have areas tinged with tans, greens, purples and other colors, depending upon the constituents of the raw materials, or materials purposely added in order to secure the desired colors, and the atmosphere of the furnace.

These cut surfaces may, 'if desired, be exposed to a flame containing oxygen which will color them to shades approximating those to which the same material burns in a, brick. The exterior upper surface'sH, which have not been out, have approximately the color of brick burned from the same material,

under like oxidizing or reducing conditions, and present a rough and pebbled appearance and texture, owing to the irregular protrusion of the original particles. The outer skin, however, extends continuously, due to the fusing of the particles together, and the under surfaceand side surfaces which have had contact with the side form or with-the operate extended slab of material of indefinite length,

parting material are likewise roughened, but to a lesser degree than the top, and usually retains a thin layer or particles of the parting medium used which has adhered intimately. v

This product issuitablefor many uses as formed by the welding of successive charges of raw materiaheach to the preceding charge, although it will be understood that the furnace construction herein shown is intended for purposes of illustration only.

In the present instance, the furnace includes a rotary preheater I, which is arranged atan incline and which serves to initially heat the granular material to-between 1500 and 1800 F., and thereafter deliver it with a minimum loss of heat into a chute J which extends above the roof of a stationary kiln K within which the material is bloated.

As shown, provision is made for the delivery of a coating or layer of sand or other refractory parting or lubricating material from a hopper L. The bloating kiln is provided with a slabM upon which a thin layer of sand is spread, and above the same the )relieated ranular ar illaceous material is,

spread in the form of a layer which is preferably defined alongits sides by the provision of side forms of the character heretofore described.

In order to properly distribute the sand over the surface of the slab and to deposit the layers of argillaceous material thereon, in uniform depth, a charging chute N is provided which as shown is in the form of a flanged plate suitably mounted on rollers O or the like, and adapted to be projected obliquely downward or otherwise into the furnace to bring its lower or discharging end into proximity with the slab M. When in charging position, sand may be delivered from the hopper L, and by Withdrawing the charging chute at a uniform rate, a thin layer or coating of sand will be deposited upon the slab M. Thereafter the charging chute may again be inserted to bring its discharging end into close proximity to the slab, and

granular argillaceous material from the hopper J be discharged in a uniform stream onto the charging chute. while the latter-is withdrawn to uniformly distribute the argillaceous material in a layer or deposit above the sand. After the charge has been'thus properly distributed it is permitted to remain in a quiescent-state -until the bloating occurs tothe desired degree. 1

In the drawings, 1 indicates a charge which has been bloated and moved into the annealing chamber Q, which may be of any desired length required to make provision for the annealing of a slab or column of the desired length.

R represents a charge of the granular material before it has been bloated, and it will be noted that the charge R contacts with the terminal edge ofthe bloated charge P, so that when bloating occurs the charge R will unite with the previously bloated charge in the formation. of a continuous unified slab or column.

The removal of each bloated charge from the bloating chamber to the annealing chamber may be effected by the action of a push bar S, which may be thrust inwardly into the bloating chamber in conjunction with the action of rollers T, which engage the completed slab within the annealin g chamber and serve to draw it forwardly concurrently with the inward thrust of the push bar S so as to prevent buckling or bulging, due to the thrust of the bar against the'end of the still plastic bloated charge still within the bloating chamber. 7

It is preferred to make provision. for the withdrawal of the pulling rollers T from the heat of the annealing chamber save when the action of the rollers is required in forwarding the slab or column, and for this purpose the rollers are arranged to be separated and withdrawn bodily from the heat of the annealing chamber during the intervals when their use is 'not required. Pulling rollers maybe located or placed at the end of said annealing chamber and so engage the cooled column.

Where it is required to roll the surface of the slab, a roller U may be provided which as shown runs crosswise of the slab while it lies within the bloating chamber, although in many cases it will be unnecessary to rollor otherwise modify the surface ofthe material in any way. v

Asthe material passes from the annealing chamber, it may be cutby the action of cutting saws or disks V, one of which as shown is arranged to cut the-slab transversely while the other is arranged to cut it longitudinally in the production of bricks or blocks I X of the desired size.

The above arrangement enables the process to be carried on by intermittent stages, so

that as one charge is completely bloated itwill be followed by another charge in the production of a continuous slab. If desired,

however, the feeding of the material may be continuous, and the slab may be constantly moved forwardly, so that ranular material will be added to the end the continuously advancing slab or column in the form of small increments or accretions rather than in the 5 form of definitely delivered charges, in which carrying out the principal steps of the process may be made, and numerous variations in form of the apparatus may be employed without departing from the spirit of the invention, and it will beunderstood that the apparatus shown serves merely for the purpose of illustrating a convenient and simplified means of carrying on the process of the present invention.

We claim:

1. The process of producing a block of material of substantially predetermined dimensions, which consists in breaking up earthly material into the form of granules of a size adapted to be spread out in the form of a sub- 5 stantially level layer, piling the mass of granular material in the form of a level layer of substantially uniform depth, and subjecting said layer, without agitation, to an externally maintained bloating temperature to cause the initielformation of a continuously extending surface film, and the formation of a unitary cellular structure throughout the mass.

2. The process of producing a block of material of substantially predetermined dimensions, which consists in breaking up earthy material into the form of granules of a size adapted to be spread out in the form of a substantially level layer, subjecting the granular particles to a preliminary treatment under agitation and to a temperature not exceeding that at which the particles retain their granular condition, piling the mass of granular material in the form of a level layer of substantially uniform depth, and subjecting said layer, Without agitation, to a bloating temperature to cause the initial formation of a continuously extending surface film, and the formation of a unitary cellular "structure 9 throughout the mass.

3. The process of heating broken up argillaceous material under agitation to a temperature not exceeding that at which the particles retain their granular condition, contini uing the heating at a higher temperature and with the material in non-agitated condition, thereby initially forming a fused surface coating constituting a sealing skin that imprisons the air between the inner particles,

and as it penetrates welds the buried particles together, expands the imprisoned air and libcrates and expands the heat generated gases so that the mass of material while in fused condition expands or bloats, and with-drawing the bloated material from the zone of higher temperature while in a cellular condi- I tion.

4. The process of heating broken up argillaceous material under agitation to a temperature not exceedingthat at which the particles retain their granular. condition, continuing the heating at a higher temperature and with the material in non-agitated condition, thereby initially forming a fused surface coating constituting a sealing skin that imprisons the air between the inner particles, and as it penetrates welds the buried particles-together, expands the imprisoned air, and liberates and expands the heat generated gases so that the mass of material while in fused condition expands or bloats, withdrawing the bloated material from the zone of higher temperature while in a cellular condition, and dividing the bloated mass into units of the desired size.

5. The process of bloating broken up earthy material in granular form in the pro-' duction of a column of cellular material, which consists in introducing succeeding layers of earthy material while in granular form, and in d sits of uniform depth, into a confined heat z ne maintained at a bloating temperature, and in bringing such deposits into edge contacting relation with one another so that they become fused together in a continuous cellular slab. i

6. The process of bloating broken up earthy material in granular form within a confined heat zone and at an externally maintained bloating temperature, and in contact with a layer of loose refractory material adapted to prevent adhesion of the bloated material to the supporting surface, and serving as a parting and lubricating medium to permit removal of the bloated mam from the heat zone.

7. The process of heating broken up preheated earthy material in granular form within a confined heatzone and at an externally maintained bloating temperature, and in contact with a layer of loose refractory material adapted to prevent adhesion of the bloated material to the sup-porting surface, and serving as a parting and lubricating medium to permit removal of the bloated mass from the heat zone.

8. The process of producing cellular building units of exact dimensions from earthy material, which consists in preheating the material in granular form, introducing successive charges of the preheated granular material into a confined heat zone at a temperature adapted by the application of external heat to fuse the particles of each charge and produce a bloated mass, each succeeding charge being fused and bonded to the preration of perature and atmospheric content during the into a heat zone at a cessive charges of the preheated material into a confined heat zone maintained by the application of external heat at a temperature adapted to fuse the particles of each' charge and produce a bloated mass, each succeeding charge being fused and bonded to the preceding bloated mass to produce a continuous column, and slowly cooling the column as it emerges from the heat zone to. prevent shattering from temperature shock.

10. The process of producing cellular building units of exact dimensions from earthy material, which consists in preheating the material in granular form, introducing successive charges of the preheated material into a heat zone at a temperature adapted to fuse the particles of each char e and produce a bloated mass, each succee ing charge being fused and bonded to the preceding bloated mass to produce a continuous column, slowly cooling the column as it merges from the heat zone to prevent shattering from temperature shock, and producing desired colothe material by controlling the temcooling operation, and dividing the mass into portions of the desired size and shape.

11. The process of producing cellular building units of exact dimensions from earthy material, which consists in preheating the material in granular form, introducing successive charges of the preheated material temperature adapted to fuse the particles of each charge and produce a bloated mass, each succeeding charge being fused and bonded to the preceding bloated mass to produce a continuous column, slowly cooling the column as it emerges from the heat zone, to prevent shattering from temperature shock, dividing portions of the desired size and shape from the mass, and producing the desired surface coloration by heat treatment under proper atmospheric conditions.

12. The process of producing a cellular mass from small particles of earthy material maintained in. a uiescent state, which includes the initial ormation of an envelope or skin of the fused materialaround the entire mass of granular particles to prevent the escape of the gases formed on the interior, and a subsequent fusing and bloating of the interior portions of the mass to form a cellular product.

13. The process of producing a cellular product from earthy material in granular form, which'consists in preheating the mate-co product from granular earthy material,

15. The process of heating broken up argillaceous material under agitation in akiln to a uniformly distributed temperature lower than that at which it becomes sticky, continuing the heating but at a higher temperature and with the material non-agitated, thereby bloating or expanding the material, and cooling the material to rigidity and to a handling temperature by cooling slowly enough to prevent contraction cracking.

16. The process of heating broken up argillaceous material under agitation in a kiln to a' uniformly distributed temperature not exceeding that at which it becomes sticky, continuing the heating but at a higher temperature and with the material non-agitated, thereby bloating or expanding the material, cooling the material to rigidity and to a handling temperature by cooling slowly enough to prevent contraction cracking, and shaping the material into articles of manufacture.

17. The process of heating'broken up argillaceous material under agitation in a kiln to a uniformly distributed temperature below that at which it becomes sticky, placing the so heated material on a thin layer of a parting material in a non-agitated state in a kiln or furnace in such a formed deposit as will contribute to its later assuming a somewhat predetermined shape, continuing the heating but at a higher temperature and with the material non-agitated, thereby bloating or expanding the material, and cooling the material to rigidity and to a handling tempera- .ture by cooling slowly enough to prevent contraction cracking. 7.

18. The process of heating broken up argillaceous material under agitation in a kiln toa uniformly distributed temperature below that at which it becomes sticky, placing the so heated material on a thin layer of a parting material in a non-agitated state in a kiln or furnace in such a formed deposit as will contribute to its later assuming a somewhat predetermined shape, continuing the heating but at a higher temperature and with the material non-agitated, thereby bloating or expanding the material, cooling the material to rigidity and to a handling temperature by cooling slowly enough to prevent contraction cracking, and shapingthe material into articles of manufacture.

a formed deposit as will contribute to its later assuming a somewhat predetermined shape,

continuing heating the so deposited material to a higher temperature at which first the surface particles of the deposit fuse together forming a continuous sealing skin that imprisons the air between the inner particles, and then as it penetrates welds the buried particles together, expands the imprisoned air, and liberates and expands the heat generated gases so that the mass'ofmaterial while in a fused condition expands or bloats, cooling the material to rigidity and to a handling temperature by cooling slowly enough to prevent contraction cracking.

20.- The process of heating broken up argillaceous material under agitation to a uniformly distributed temperature below that at which it becomes sticky, placing the so heated material on a thin layer of parting material under quiescent conditions in such a formed deposit as will contribute to its later 4 assuming a, somewhat predetermined shape,

continuing the heating of the so deposited material to a higher temperature at which first the surface particles of the deposit fuse together forming a sealing skin that imprisons the air between the inner particles, and then as it penetrates welds the buried particles together, expands the imprisoned air,

and liberates and expands the heat generated gases, so that the mass of material expands or a heat zone, leveling off the materialfto the' desired depth, spreading a specially prepared layer of granular material over the surface to give the desired surface texture, and heating the material at a temperature adapted to first cause the formation by fusion of a surface skin, and thereafter cause bloating by the expansion of the material due to the evolution of gases within the interior.

22. The process of producing cellular building material, which consists in first preheating earthy material-in granular form at a temperature below that which causes fusion of the material and in a non-oxidizing atmosphere, second in transferring the heat ed material to a heat zone elevated to a bloating temperature and in depositing the preheated material in the form of a layer of substantially uniform depth, and in bloat-ing the material thus deposited in a non-oxidizing atmosphere, and third in transferring the material, after bloating, to an annealing zone and, allowing the material to slowly cool in an oxidizing atmopshere.

23. The' process of producing cellular building material, which consists in subjecting earthy material in granular form to preheating at a temperature below that of fusion and ma non-oxidizing atmosphere, second in treating the material while in the form of' a layer of substantially uniform depth to a temperature suflicient to cause the formation by fusion of a surface skin, followed by bloating due to the evolution of gases in the interior of the mass and in anon-oxydizing atmosphere, and third in annealing the material in an oxidizing atmosphere.

24;. The process of bloating broken up earthy material in granular form in the production of a column of cellular material which consists in introducing succeeding layers of earthy material while in the granular form within a confined heat zone maintained at a bloating temperature and in bringing such deposits into contacting relation with one another so that they become fused together ina continuous cellular mass.

25. The process of bloating broken up earthy material in granular form in the production of a column of cellular material which consists in introducing a layer of earthy material while in granular form into a confined heat zone maintained at a bloating temperature and in bloat-ing such deposited layer within the heat Zone and in then depositing a succeeding layer in granular form in contact with a portion of the surface of the already bloated layer to cause bloating of the last deposited layer, and fusion thereof to the previously bloated layer in the formation of a continuous cellular mass.

26. The process of manufacturing light weight construction materials from argillaceous materials consisting in heating the raw materials to a relatively high temperature while movingf through' a closure relatively free from'ox'y'gem 1 27. The process of ia'nufacturing light weight construction materials from argillaceous materials consisting in heating the raw materials to a relatively high temperature while'moving within and through a closure relatively free from oxygen and subsequently cooling the same.

28. The process of manufacturing light weight construction materials from argillaceous materials consisting in heating the raw materials to a relatively high temperature for a relatively short time while moving through a closure relatively free from oxygen suflicient to bring the heated materials to a swollen and cellular condition and subsequently cooling ,the materials.-

29. The process of manufacturing light weight aggregate structural units consisting 1n subjecting the materials to a relatively high temperature within a closure relative- 1y free from oxygen for a relatively short time while moving therethrough and subsetime while moving therethrough and forming the heated materials while still hot into structural units of predetermined sizes and shapes and subsequently cooling the materials.

32. The process of manufacturing light weight a gregate construction units consisting in su j ecting the materials to a relatively high temperature within a closure relatively free from oxygen for a relatively short time and forming the heated materials While still hot into structural units of predetermined sizes and shapes and subsequently cool- 36. The process of manufacturing light weight aggregate structural materials consisting in sub ecting raw argillaceous materials to a relatively high temperature in a closure relatively free from oxygen for a relatively short time under pressure and discharging the heated materials by pressure while hot.

37. The process of manufacturing light weight aggregate structural materials consisting in sub ecting raw argillaceous materials to a relatively high temperature in a clo'- sure relatively free from oxygen for a relatively short time under pressure and discharging the heated materials by pressure I while hot, cooling and subsequently cutting the discharged materials into structural units of predetermined sizes and shapes.

KEMPER SLIDELL. SHERMAN Q. LEE.

ing the materials and after cooling cut into I other desired sizes and shapes.

33. The process of manufacturing light weight aggregate structural units consist-ing in subjecting the materials to a relatively high temperature within a closure relatively free from oxygen suflicient to bring the heated materials up to a cellular condition for a relatively short time and forming the heated materials into structural units of predetermined sizes and shapes and subsequent- 1y cooling the heated materials.

34. The process of manufacturing light weight aggregate structural units consisting in subjecting the materials to a relatively high temperature within a closure relatively free from oxygen suflicient to bring the heated materials up to a cellular and spongy condition for a relatively short time and forming the heated materials into structural units of predetermined sizes and shapes before cooling, and after cooling cut into other desired smaller sizes and shapes.

35. The process of manufacturing light weight aggregate structural materials consisting in subjecting raw argillaceous materials to a relatively high temperature in a closure relatively free from oxygen for a relatively short time under pressure and removing the heated mixture from the closure by pressure while hot.. 

